


Grimm and Bear Them

by BioYuGi



Category: RWBY
Genre: Breast Expansion, Broodmother - Freeform, Butt Expansion, Corruption, Grimm - Freeform, Grimmification (RWBY), MultiBreast
Language: English
Status: Completed
Published: 2020-12-17
Updated: 2020-12-17
Packaged: 2021-03-10 21:14:02
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,075
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28123656
Author URL: https://archiveofourown.org/users/BioYuGi/pseuds/BioYuGi
Summary: On the third day of Bio's new perv reality:Grimm corruption!After the very cuddly, warm, fluffy story yesterday, now we do the complete opposite tonally. What happens when Cinder somehow reaches a new level of desperation? Is she willing to give up what remains of her humanity for a chance at power? Yes, and it comes with quite a lot of advantages and changes to her body.
Kudos: 10





	Grimm and Bear Them

"AGAIN!" Cinder shouted, pounding a fist against the wall. "EVERY TIME! Why? Why can't I win?! Those brats… every time they get in my way they manage to win. It doesn't make any sense!" Every few seconds, her right arm slammed into the walls of the castle, still not managing to make a dent in the twisted, ebony architecture. This only frustrated Cinder more as it made her realize how weak she was in the grand scheme of things. She screamed loud enough to make her throat wince in agony.

Then with another twisted howl of pain, she ripped off the frayed edges from her dress's left sleeve. Revealing that her Shadow Hand prosthesis had once more been destroyed. Cinder stepped deeper into Salem's domain, where the night seemed endless, and every room felt like it was claustrophobic no matter how large it was. With each step forward, Cinder pressed her jaw tightly closed, trying to stifle the sensation of her arm growing back into place. It was never pleasant, and she hated how she already knew that from past experiences.

"Grragh! I don't understand," she spat, walking through the rooms. In her right, still-human arm, she lit up a flame. Her left arm finished growing and she stretched the clawing, shadowy mass out in front of her as well. Cinder's eyes lit up with her maiden powers, flames flickering back at her short black hair. The black glass she kept over her blinded eye melted and reformed in her right hand as a simple dagger. "I have my semblance, I have MY maiden powers, I have Grimm strength." Her face was getting numb as frustration built up in her.

She wasn't even sure which room she was in when she exploded everything outward, leaving scratch marks, burn marks, and broken glass strewn behind her. Her vision was hazy. Breathing felt painful from how hot her breath was, with every drop of saliva in her mouth feeling like she was producing lava. Her left arm wrapped around a column in her way and attempted to pull it down. She left a few dings in it, but nothing substantial, and as flames cascaded over it Cinder saw little more than embers licking at the floor behind it. Even here she felt powerless.

"Damn it. DAMN IT!" Cinder yelled. She forced herself to stay upright no matter how badly instincts wanted her to fall down to her knees. But she stayed still, simply seething, until her Grimm arm twitched. Cinder looked up and saw it physically pointing to the bubbling pool of Grimm Liquid in the center of the room. With a quick clench of her arm, Cinder was able to bring the hand back under her control, while she stepped towards the pool. Even with only one eye she could see how deep it was. It looked nearly endless. Regardless of what consequences might arise from falling into the pit of black tar itself, if you tried to swim to the bottom, it might never be reached.

Cinder hadn't been conscious when Salem attached the Shadow Hand to the stump of her shoulder. Since then she'd wondered how helpful it had been. It burned when Ruby used her Silver Eyes, it sometimes felt out of her control, and it made her feel… inhuman. Less complete than if she'd been left without an arm to begin with. It wasn't as if getting technological prostheses were out of her power. Had she done it thinking it would help? For punishment? Cinder clawed at her scarred eye wondering why she didn't bother implanting something in her head as well, just to really rub it in.

"..." She stared pensive at the mass. It looked as if a gigantic Grimm could ooze out into existence at any moment. Volatile, bubbling black that seemed more alive than it should be. "Fine," Cinder growled. She placed her left foot into the pool, and felt a sting as it stuck to her foot. It quickly felt like it was trying to pull her into its depths, but using the stretchiness of her left limb she was able to stay out of it by wrapping her arm around another column. "I need more strength," she reasoned. "So give it to me."

Cinder plunged her leg in all the way up to the knee. The sensation was far less painful than she expected, barely more than if she were to step into a hot tub without preparation. There wasn't much of a splash from the forceful penetration, but some of it still slapped itself against her thigh as she pulled it out. Immediately she felt a powerful force surge through her. The legging and boot she had on that leg melted around her limb, leaving it bare as the shadowy energy wormed its way into her. She growled, feeling a feral heat come through her body as she stumbled in place.

"Nnngnghghgh, hahhh, I can handle it," she assured herself, biting down on her lip. Her skin felt like it was being massaged all over by the evil force, getting deep into her core until her entire leg looked entirely black. Cinder groaned as her toes split apart and she felt the ends hardening into more white claws. Her heel forced itself off of the ground, and jut out further, like a high heel had formed permanently on her sole. The spiked end jabbed itself into the ground, as black oozed around her leg to ensure it was defined. Her calve was wound up with two smaller segments that curled up together like a DNA strand before joining at the knee. From there, black crystallized joints burst out at all angles before her thigh gained its strength and filled out. By the time the corruption was finished with her left leg, Cinder's thigh was significantly bigger than its opposite, but that felt like a problem she could deal with. 

"Hahhh, wow," she said, smirking. "That felt… good," she moaned, licking her lips as she noticed the lack of scars from what had once been her left leg. Some of the Grimm essence trickled up towards her waist, with purplish-black veins creeping a few inches before they stopped. That was nothing new, her shoulder had the same deformity, as more of the liquid mixed in with her vital fluids. Cinder tore off more of her dress now, and saw the singed half of her body, noting the way her arm and leg looked like they were trying to meet in the middle. 

"Not yet," she muttered. Cinder dunked her Grimm arm back into the pool and came back out with a handful of the raven-colored gunk. She slapped it on her face where her eye was wounded, and the scar tissue spread out. "Nnngghah! Hahhh, yes!" she cried out. This time it wasn't just corrupting her flesh, it was seeping into her being. Her vision grew muddier for a few seconds before it returned to her. Now her left eye felt functional, but it wasn't the same as normal. In between the normal colors in Evernight she saw hues she'd never seen before. She could somehow grasp where the temperature in the room was focused, and saw soft waves of sound coming out of the pool.

"Nnngh, hahh, I can control it. I can handle it. I can control it. I can HANDLE it!" she screamed to herself even as it was somewhat apparent that her words carried less truth. The hair on the left side of her head began to droop, as it lost its fancy coif. She winced a few times as it seeped deeper into her body. She couldn't tell that her left eye was now pitch black with a yellow slit pupil in the center. It narrowed as the rest of her face absorbed more of the liquid, changing her skin to black. Starting in the back of her jaw, her teeth began to lengthen and sharpen, giving her some fangs that increased in number every few seconds. Some of the teeth split into two, giving her more teeth on the left side of her mouth than she should have had.

"More, no, no, this is good," Cinder said, trying to reason with herself. Her hair lengthened, while more crystals of darkness formed in her locks of already-shadowy hair. White bone fragments stuck to her flesh along the width of her scar, reaching out a bit further than it spread originally. Cinder ran her hand through her hair, and more of the liquid dripped off of her locks. With her body half-exposed from the tears she'd formed in her dress, some of it fell onto her exposed breast.

"Mmmngh… that's good," she whispered. Cinder was unaware that black splotches had formed on her left tit. The nipple stained itself white as the corruption spread across her boob, to the point it swelled with literal dark energies. It bloomed out into another cup size, with the areola widening, and her nipple thickening up on top of that. The heat that came from the liquid filled her further, to the point she felt like she was perspiring. But what crept out of her skin wasn't clear, it was dark, and dripped down the sides of her neck and onto her back. 

"Mmmaybe, I should, nnngh. I might get in trouble if, no, no, damn her if she didn't grant this power to me willingly," Cinder grumbled. She dipped her human hand into the pool, and felt her finger melting. But before she'd pulled it out, they'd reformed, with her digits tipped with small, thin stingers, like a scorpion's tail. Each finger was thicker and longer, wriggling around like tentacles. She stared at it for a moment, a brief moment of concern about what she was doing to herself. Then she grabbed another mass, watching it slip through her tentacle fingers. The corruption spread down her forearm. But instead of ending up the same, spindly, stretchy style as her left arm, it felt bulkier, with a ridge of spiked pieces forming every few inches.

"It feels so good though," she moaned. Cinder slapped that mass of gunk onto her torso, letting it seep into her very essence. Her left breast expanded yet again, outsizing her right while the newly-corrupted boob worked to catch up. She opened her mouth to lick her lips, with her tongue now transformed into a slithering, lengthy muscle with a black, fork-tipped tongue. Ooze dripped from its tip, onto her stomach as she leaned her head back. White spots appeared on top of the black where her torso was shifting, forcing more flesh to coalesce in its place.

"I need more, I want more," she gasped. Her hips cracked as more weight added itself to her chest. Now her breasts had grown out to be a heavier, denser rack, jiggling with evil. She cackled, well aware at this point that she'd gone too far but unwilling to stop. Figuring that it wouldn't even matter at this point, and relishing in that realization. "Hahahaha!" Her voice even sounded deeper, like the blackness creeping down her throat was changing her from the inside out. Cinder cackled and ran her changed arms across her midsection, feeling the weight of her chest equalize as her original breasts caught up to each other and the nascent pair beneath them began their growth. 

The more she slathered on herself, the bigger Cinder seemed to get. Her height was slowly but steadily increasing. The heel on her left foot which had formed into a sharp spike elongated to compensate as her legs grew longer with every passing moment. Cinder's hips cracked and began to spread outwards, thickening her entire lower body in the process. The remains of her dress were damaged even further as something burst from above her backside. A spiky, thick tail nearly as wide as her torso exploded into existence, and thinned as it reached down to the ground. While the growth of a new arm had once been agonizing, Cinder's womanhood felt enticed by the bursts of energy that were needed to change her body so extensively.

Her tail was thick, and her butt became doughy as well. Underneath it was clear she still had musculature. The power of the Grimm came with heavily-increased strength, and she'd been empowered with far too much. But, there was an undeniable, enticing wobble to her exposed butt cheeks. Cinder tore the rest of her outfit off as she gave way to the corruption taking over her. Any attempt she might have made to 'control' it ceased. Giving in felt so good that she didn't quite care if she retained herself at this point. The power and body was too great to ignore. Soon Cinder had a worthy set of child-bearing hips that were each half a foot wider than they'd been to start, and her tail smacked into the ground with a massive, drooling maw attached at the end.

"Hahhh, hahhh, hahahahaha!" Cinder's voice deepened further as she manhandled her chests, now that the splotches had formed into a softer, smaller second set. But they were pumping up bigger by the second, and their growth only increased when Cinder's tail dunked itself into the pool. The mouth on it looked to literally be drinking the concoction, to the point her breasts may as well have begun to fill with it. But a squeeze on her lower, melon-sized breast didn't produce any black milk just yet.

Her mad laughter continued as she caressed her torso, which seemed to widen just like her hips had. It pushed outward as well, swelling into a small dome that pushed her lower breasts further apart. While her stomach increased in mass and thin white lines appeared on its charcoal surface, her breasts expanded in magnitude again. They more than doubled their mass in so short a time that she nearly toppled forward if it weren't for her tail and ass providing some counterbalance. Now each was what she might have called overly-large before rational thought left her brain, each mound enough to dominate a weaker woman's torso. The four spheres, each bigger than a beachball, bounced against her firm midsection which still had room to grow. Her navel vanished, leaving behind just a pulsating white and red mark in the dead center of her belly.

"I'll show them," she said, suspiciously quietly as she used her larger, more muscular right arm to smash into the ground. Now there was a cracked surface from the impact, instead of a weak thud. Cinder's hair continued to grow, but at a certain point it stopped resembling hair, for hair wasn't supposed to writhe and squirm as if it were alive. Cinder groaned in bliss as her body jutted to the side, and right between her shoulders and her tail burst forth two sets of wings. They were uneven as well, the left firm and draconic in nature while the right seemed more batlike. Her humanity looked to be a remnant, with more and more corruption dominating her body. Barely any patch of human skin remained on her, just an inch or two around her right eye.

As more of the liquid seeped into her body, Cinder grew taller yet again. She already began to dominate in size over any human she'd met, now she towered over them. Her clawed feet mashed into the ground, quadruple the size of what they once were. The woman's thighs looked capable of crushing a cinderblock to dust if placed between them, while her tail could easily handle the task of coiling and devouring anyone who tried to sneak up behind her. Her hips were at least four feet wide, with a bulging, moist labia pulsing out in front of her. She gnashed her razor-sharp teeth together as a new need was instilled in her. With this body and all the Grimm liquid she'd absorbed, and now produced, she was ripe to make an army of her own. The gigantic spherical tummy that stood out against the gnashing, gnarled, twisted body she'd grown was evidence that she was already undergoing a process to birth more.

"Mmmngngh, yesssss," she growled. Her dark, long tongue slipped out of her shark-like jaw and dripped her corruptive drool onto her breasts. Each of the four spheres was enormous in size, the size of immense yoga balls. On her tall, imposing frame, they looked more in-place than if they were on a regular-sized woman, but there was enough titflesh on her torso to easily smother a quartet of hunters and huntresses to unconsciousness. Her nipples felt like paint cans on top of bowl-sized areolae. The sloshing indicated they were ready to expel their bounty at any time. The sounds that came from Cinder were utterly inhuman, but what could be expected when her very insides had rearranged to suit her new purpose. If Emerald were to see her now, the green-haired sycophant would need to back up just to gaze at Cinder's gravitude.

Her remaining human feature of that right amber eye still stared ahead defiantly as her flame powers formed alongside it. She brought her hands together and watched the embers course along her flesh. Some of the patches on her skin hardened and turned ivory as they solidified into chunks of armor plating on her shoulders and sides. Her jaw elongated, becoming more feral in return for a larger bite radius. Cinder realized she'd been able to take several steps without any issue, and with a jump in the air, her wings needed to beat only a few times to keep her airborne. She slammed back into the ground with a heavy thud, creating a mild crater solely from her brief fall.

"I'll… win," she gnashed. Speech felt more difficult now. Maybe she'd get used to it again but the powers flowing through her made such acts a distraction. Cinder placed her original Shadow Hand on the turgid mass of her gut, still able to reach it despite how big it had grown. If it weren't for the horrific amount of spikes, or the corruptive liquid that oozed out of her, or the pure aura of malevolence that emanated off of her, Cinder's figure might have been seen as appealing. But she couldn't care less about such matters right now, she had business to tend to, and a far-too-joyful group of people to corrupt.


End file.
